This is a basic engine like the old junior modell.
Max RR3, Old RB Rody and JP FX engine was based on the same.
It has an old Efra crankshaft with a small hole in it and will give you long run time.
It's a very good engine for the money and should be used with 2601,2602 and 2604 pipe. Can also use 2669 pipe.
Easy to modifie if you know what you do.
It's not based on the legendary +12 engine